Method of making electric conduits.



METHODl 0F MAK-ING ELECTFHCv CONDUITS. l {Application filed Dec. 2, 190m "No Model.)

" iff. u W HWI u V V 4 HUM M l mllul mi v UNrrsn Sterns PATENT OFFICE.

AMANDA M. LOUGEE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO CLIFTON MANUFACTURING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORA- TION OF NEV JERSEY.

METHODv OF MAKING ELECTRIC CONDUI'OI'S.

SPECIFICATION forming' part of Letters 'fatent No. 713,122, dated November 11, 1902.

I Application tiled December 2, 1901. SerialNo. 84,344. (No model.)

T @ZZ whom, it puny coi/werft:

Be it known that I,AMANDA M. LOUGEE, a citizen of the United States, residing at Boston, county ofSuffolk, State of Massachusetts,

have invented an Improvement in Methods of Making Electric Conduits, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like 1o parts.

My present invention is a method of manufacturing electric conduits of the kind in which there is an outside armor provided with an interior lining or insnlating member formed as nearly as possiblel integrally with said armor and preferably being capable of being made as nearly as possible like'a coating-t'. e., being so thin and occupying such intimate relation to the armor as to be more zo like a skin or coating of the armor than a separate tube secured thereto.

There has always been great difficulty in obtaining a' substantial insulating member properly united to the armor; and accordingly z5 my present invention has for oneV object the provision of a method whereby the resulting conduit has its insulating member or interior lining and the armor oroutside covering prac,

tically integral at alll points, this result being 3e obtained, moreover, withoutv the sacrifice of any of the desirable qualities essential to a` superior conduit, but, on the contrary, my.

method includes certain steps which produce a much more efficient conduit in respect to flexibility, insulation, durability, adaptability to all positionsand kinds or usage and manipulation, besides other features, such as fire-resisting capacity, all as will more fullythe trade.

inner surface of great insulating and lireproof 5o qualities with an intermediate softer layer capable of great flexibility.

For the purpose of a clear understanding of my method I have illustrated in accompanying drawings the steps thereof as taken by me in the manufacture of one form of armored conduit.

Figure l is a fragmentary plan view of a sheet properly prepared prior to being formed for insertion in the armor. Figs. 2 and 3 are 6o plan views, partly in section, showing an armor in the process of being provided with the insulating-lining. Fig.4isaper spectiveview of a mandrel which may be employed. Fig.

5 is a longitudinal sectional view showing a 65 further step in the process.

Y In carrying out my method I do not intend toy limit myself to any set way of making a conduit; but for purposes of illustration herein I refer to that method in which the various 7o layers which constitute the lining of the conduit are prepared in sheet form before they are formed into tubular shape for insertion within the armor.

" Bearing iu mind that one of my purposes rspread upon a suitable base or support o.,

such as cotton fabric, (reference'may be had tomy Patent No. 642,539, dated January 30, 1900,) a thin layer of asbestos, mica, or other fire-resisting material, as will be more fully defined later on, contained in a vulcanizingvehicle or binding agent, preferably rubber or the like, containing sulfur, antimony, or other vulcanizing ingredients well knownto This layer is made of a service- 9o able thickness, and as it is extremely lireproof and contains its own hardeningagents (when subsequently vulcanized) it may be much thinner than has heretofore been possible. 'lhis layer constitutes also a virtual 95 protector for the next layer or layers toV be described. On this first layer (and it will be understood that it may consist of as many coats of the material as required to form the thickness desired) I spread a layer of pliable material, such as rubber or the like, this layer being preferably composed of a number of coats of rubber, and preferably the amount of sulfur or other vulcanizing agent is used in diminishing quantities in the successive coats from the first. coat of the ireproof layer to the last coat of the pliable layer, the result being that when vulcanized the hardest finish is given to the exposed surface and the increasing pliability results between said surface and the adhesive or binding parts nextv to the armor.

I-laving prepared the sheet composed of its successive layers, as above stated, I provide the inside of the armor-tube with a special cementitious coating and also preferably place a similar coating on the last layer of the insulating-sheet, then dry said cementitions coatings.- I dry the armor with hea't, so as to expel all moisture possible and render the cementing solution as dry and permanent in position as possible, that when subsequently the lining is inserted and heat applied, as will be presently explained, there may be no possibility of the union being rendered imperfect by reason of gases, bubbles, or other imperfections due to the presence of moisture or volatile ingredients, and also that the layer of cementitious material may remain uniform and not be dislodged or wiped olf by the sliding action thereon of the insulating layer as the latter is inserted within the armor-tube.

One of the important features of my conduit resides in having the lining and armor joined together as nearly integral as possible, this union being much more perfect than by any simple cementing. I accomplish this and I also accomplish a second exceedingly desirable result-namely, the making of the insulating-lining of any extreme thinness desired, as already mentioned, and that without sacrificing any of the insulating or lireproof qualitiesby vulcanizing the lining directly to the armor, the latter being preferably iron. Iaccomplish this, moreover, in such a manner that the lining is not stuck to the armor, but is chemically united--that is to say, I do not depend upon aline of adhesion, such as would exist between two pieces glued orstuck together by a regularcom pound, such as has heretofore been employed; but I use Such substances and in such a manner that the lining and armor constitute practically one piece, the substance used consisting, preferably, of the fundamental ingredients of the lining material itself, so that after the subsequent vulcanizing step in the process there is really no third material between the lining andthe armor; but the adhesive layer originally applied has disappeared as such and has actually become a part of the armor and lining. The cementitious substance or coating is composed of some duid solventsuch as naphtha, benz'ol, dac., bisultid of carbon being preferably added and used therewith as the vehicleas this solvent facilitates the disintegrating of or perfect formation of a solution of rubber, sulfur, and litharge, (it being understood by those skilled in the art that the usual ingredients of rubber compounds may be used, including a drier and vulcanizing agency,) the bisultid of carbon changing the nature of the ingredients to such a state as to produce a freely-owing fiuid capable of being freely run through any pipe, however small, thereby leaving a complete coating thereof, and yet a thin coating. I have found that this solvent will contain in solution a very large percentage of sulfur.

Having prepared the armor and lining as stated, the lining is properly inserted in the armor and is then forced radially outward at all points into direct contact with the armor byanysuitable means, as by a sectional mandrel, whereupon it is subjected to a Vulcanizing heat suicient to melt the cemenlitious layer or layers and perform the vulcanizing step of the process, which completes the perfect union of the lining and armor. Finally, the fabric foundation is withdrawn in any suitable way.

It will be understood that the degree of pliability depends upon the degree of Vulcanization and upon the composition of the lining material-as, for example, the more fireresisting substance (such as asbestos, mica, and the like) that is used the greater will be the hardness of the lining, and if for certain purposes the asbestos is incorporated more or less throughout all the layers of the lining the result is that there will be very little pliability. This brings me to a further step in my process, this step being employed according to whether I am producing a conduit of little pliability or not. I may also remark that this step is of service when I am making a conduit in which the lining is composed of vulcanite or other substance which after vulcanization or formation is not pliable. The step referred to consists of withdrawing from the conduit the mandrel before vulcanization or when the vulcanization has proceeded part way only and then subjecting the conduit to such bending and shaping as may be required to have it conform to its eventual installation shape, this bending taking place while thelining material is still in a plastic state and then, having properly shaped the conduit, the Vulcanization is completed.

For some purposes I find it desirable to replace the mandrel with some supporting medium for retaining the fresh or the partiallyvulcanized lining pressed tightly against the armor, and I accomplish this by compressing within the partially-vulcanized conduit such materials as Whiting, soapstone, powdered mica, the., which,while serving to sustain the lining against the armor during the bending strain and nal vulcanization, yet permit the conduit to be bent as required.

It will be understood that I have described IOC IIO

-ties desired.

the order in which I prefer to assemble and form the parts of the lining; Ybut I Wish it understood that unless otherwise specified in the claims I do not .limit myself thereto, as other means of applying the materials and layers Within the conduit may be resorted to.

The result of the successive steps which constitute my method, as above explained, is that the armor and lining constitute practically one piece, and the lining may be,if desired, as thin as a mere skin and yet possess all the requisite iiexibility and fireproof quali- The inner or exposed surface against which the Wires contact is hard and reproof, thereby being practically indestructible and also minimizing the danger from friction as the Wires are being hauled through the conduit, and between that and the iron of the armor is a soft and flexible or pliable layer, which is joined to the armor by perfect vulcanization, the vulcanizing, however, preferably not extending into a soft layer, but the sulfur or other vulcanizing agent being practically taken up by the extremely-susceptible cementitious layer and by the iron, for Which it has au affinity.

Another advantage resulting from my method is that the lining is so directly joined to the iron and is of such a resulting nature that it Will not tear or become injured by the rough cutting to which electric conduits of this kind are apt to be subjected by ordinary workmen.

It is unnecessary to explain to those skilled in the art the very great advantage resulting from my method of having the lining held absolutely to the armor at every point, so that when the conduit is bent there is no possibility of the two separating, but the adhesion and stability of the lining and armor are practically perfect.

' By my process I am enabled vto provide an interior surface of highly-insulating ingredients Which are not in themselves flexible, but are so combined as to afford a flexible layer, the conduit being capable of any degree of flexibility desired simply by varying the extent of softer material beneath the harder'inner surface and the armor.

The insulating and fire-resisting or hardening substances maybe asbestos or asbestos and mica, magnesium, lime, slate, talc, soapstone, infusorial earth, or any prepared mass or mixture of iireproof material or earthy substance, these giving not only fire-resisting qualities, but providing a sleek hard top iinish as Well.

In my present method the vulcanized conduit has rubber directly joined to rubber in the successive coatings, which results in an integral tube instead of having rubber united to the armor by an intermediate layer of some sort-as, for example, bya layer of asphalt, the latter making a poor joint, IWhereas in my present conduit thereis really no joint, inasmuch as the vulcanizing step of the process makes the mass homogeneous. Also by having all the vulcanizing take place inside the armor after the entire conduit has been assembled there is a perfect union of the lining material at the seam.

The required thickness of lining is made up by successive coatings,l as stated, formed of material giving both pliability and strength.

I wish it understood that while I prefer to employ all the steps of my method as above explained, thereby obtaining a conduit having all the ad rantages specified, yet l do Vnot intend to restrict myself thereto, as certain of the steps may be employed without the others, with a corresponding degree of resulting advantage. For instance, if the soft intermediateA layer is omitted the remaining steps of the process will yet produce a superior conduit of a more rigid character, (which,

indeed, can be made absolutely rigid by employing a vulcan ite or cclluloid composition,) and also if the tireproof exible lining should bepsecured in the armor by any of the oldthat I am not otherwise limited than as ex-i pressed in the claims.

In the draWingsI have illustrated a groundwork or foundation of fabric a., on which is spread a layer l) of iireproof composition in as many coats as desired, three being indicated, and on this is a layer of the sulfur material c, preferably also applied in a plurality of coats and covered With a cementitious layer d, the armor f having also an interior cementitious coating g. v

A preferred form of mandrel h, havinga split formation for purposes of expansion, may be employed for forcing the lining out against the interior of the armor and holding it there during vulcanization.

Having described my invention, What I claim as new, and desireto secure by Letters Patent of the United States, is-

l. Theherein-described method of making insulating-conduit, consisting in applying to the interior of the armor a cementitious coating, containing vulcanizing ingredients,forin-.

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dusted Within the armor, applying vulcanizing heat to the Whole.

3. The herein-described method'of making insulating-conduit, consisting in applying to the interior of the armor a cementitious coating, containing vulcaniziug ingredients drying said coating, forming a lining, inserting the said lining within the armoil and applying vnlcanizing heat to the whole, thereby incorporating the said vulcanizing material in the conduit.

4. The herein-described method of making insulating-conduit, consisting in forming a lining of successive layers of rubber or like substance, containing vulcanizing ingredients in successively smaller percentages, introducing said liningr within an armor, with the layer or layers containing the less amount of vulcanizing ingredients between the armor and the interior of the conduit, providing a cementitious agency for uniting the lining to the armor, and applying Vulcanizing heat to the whole.

5. The herein-described method of making insulating-conduit, consisting in forming a layer composed of lire-resisting and vulcanizable ingredients, forming a layer thereon containing rubber or the like and vulcanizing ingredients, introducing the same in an armor, providing between said armor and lining a uniting substance, and subjecting the whole to a vulcanizing heat.

6. The herein-described method of making insulating-conduit, consisting in providing an armor, forming a lining material having a Vnlcanizable surface next to said armor, providing between said armor and lining a vnlcanizing substance containing bsulid of carbon, and subjecting the whole to a vnlcanizing heat.

7. The herein-described method of making insulating-conduit, consisting in coating the interior of the armor with a cementitious solution containing bisullid of carbon, drying the same, forming a lining material having its surface next to said armor containing a Vulcanizable layer, insertingr said lining in the armor against said coating, and applying vulcanizing heat to the whole.

8. The herein-described method of making insulating-conduit, consisting in providing Within an armor a vnlcanizable lining, maintaining said lining in intimate contact with the inner surface of the armor, applying vulcanizing heat to said armor and lining, and While the lining is still plastic under the vul canizing heat bending and shaping the armor and lining as desired.

9. The herein-described method of making insulating-conduit, consisting inl providing within an armor a vulcanizable lining, filling the armor with a powdered mass capable of withstanding a vulcanizing heat, applying a Vulcanizing heat for vulcanizing the lining in and to the armor, and bending or shaping the armor and lining while still plastic and containing said powdered mass.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

AMANDA M. LOUGEE.

Witnesses:

O. J. DONLAN, M. E. CAHILL. 

